1. Technical Field
The present invention relates to a bridge for tuning octaves of strings of a string instrument, and in particular, the present invention relates to a technique for improving vibrancy of musical sound with a saddle having a simple structure.
2. Background Art
For example, a string instrument such as a guitar has a neck and a body that is provided with a bridge. The neck includes a head that is provided with pegs and includes a nut at an end portion thereof, and the bridge is provided with saddles. Ends of plural strings are anchored to the bridge, and the other ends of the strings are wound to the pegs. In this structure, a distance between the nut and the saddles is a scale length. In such string instruments, tuning is performed by adjusting tensions of the strings with the pegs.
In string instruments with frets, such as guitars, there are cases of off-pitch when a player holds down strings for performance. This is because a distance from a saddle to each fret is not suitably adjusted. Therefore, it is necessary to finely adjust the position of the saddle, that is, the scale length, with respect to each string. This adjustment is called “octave tuning”.
For example, in a folk guitar or the like, the scale length of each string is set at a most appropriate value by obliquely fixing a plate-like saddle on a bridge. On the other hand, some electric guitars have plural saddles that are separately arranged with respect to each string, and the saddles are movable by screws so as to separately tune the octaves of each string. In general, such a bridge is used in most electric guitars.
On the other hand, other kinds of electric guitars do not have saddles that are movable with respect to each string. For example, in a famous series of electric guitar called a “Telecaster” (registered trademark of Fender Musical Instruments Corporation), a bridge includes saddles that are made so as to support two strings at two ends of each saddle. This structure is fixed as a conventional design, and it provides brilliant sound that is highly regarded by musicians. Therefore, it has been difficult to modify the structure so as to separately tune each string. Accordingly, a technique for separately tuning the octaves of each string even in such a bridge is desired.
A bridge is disclosed in Japanese Unexamined Patent Application Laid-open No. 2011-197618. This bridge is formed with approximately columnar-shape saddles and rotatably supports screws at an edge portion of the plate thereof. The screws penetrate through the center portions of the saddles so that the saddles are movable. Each of the saddles is formed with a string groove at two ends for supporting a string, and the ends are eccentrically arranged at a nut side and the other side, respectively. In the saddle of such a bridge, for example, a supporting point of a first string is closer to the nut than a supporting point of a second string, whereby the scale length of the first string is shorter. The distance between the supporting points in the saddle is set so that the octave of the other string is simultaneously tuned by tuning the octave of one of the first string and the second string. The saddle for third and fourth strings and the saddle for fifth and sixth strings have the same structure as described above, whereby the octaves of all of the first to the sixth strings can be tuned.
In the bridge disclosed in Japanese Unexamined Patent Application Laid-open No. 2011-197618, each of the saddles is formed into a columnar shape in which the two ends thereof are eccentrically arranged at the nut side and the other side, respectively, with respect to the center portion of the saddle. In order to produce such a saddle, after a columnar metal material is turned, two ends must be cut so as to be eccentrically arranged with respect to the center portion. Therefore, the production process is complicated, and large amounts of material are removed in the cutting, whereby the material cost is relatively high. In addition, a portion of the saddle for supporting a string is thin due to the cutting, whereby vibrancy of sound is not superior. Moreover, since the string grooves are formed along the outer circumferences of the columnar ends, the string grooves have an arc-like cross sectional shape. Accordingly, the string grooves have a large area for contacting the string, whereby vibrancy of sound is further degraded, and chattering noise occurs in some cases.